Answer:
Amedeo Avogadro
Explanation:
Amedeo Avogadro, an Italian scientist, was the first to propose the hypothesis that, at a fixed temperature and pressure, equal volumes of different gases contain the same number of molecules. This idea is known as Avogadro's Law. Despite his contributions, Avogadro's ideas were not accepted during his lifetime, and it took some time for the community of science to fully appreciate his work.